Re: What do I do to get better curves?
- To: mathgroup at smc.vnet.net
- Subject: [mg120954] Re: What do I do to get better curves?
- From: Alois Steindl <Alois.Steindl at tuwien.ac.at>
- Date: Thu, 18 Aug 2011 03:24:43 -0400 (EDT)
- Delivered-to: l-mathgroup@mail-archive0.wolfram.com
- References: <j2g371$1ek$1@smc.vnet.net>
Am 17.08.2011 11:55, schrieb becko:
> Run the following code in mathematica:
>
> r=6197/3122;
> p[k_,w_]:=Sqrt[w^2/r^2-k^2];q[k_,w_]:=Sqrt[w^2-k^2];
> a[k_,w_,p_,q_]:=(k^2-w^2)^2 Sin[p]Cos[q]+4k^2 p q Cos[p]Sin[q]
> a[k_,w_]:=a[k,w,p[k,w],q[k,w]];
> ContourPlot[a[k,w]==0,{w,0,6},{k,0,14}]
>
> The curves thus obtained are very inaccurate. I tried raising the
> PlotPoints and WorkingPrecision opions of ContourPlot, but it doesn't
> work. Morevoer, you see that the only parameter that shows up, 'r', is
> an exact rational number. I don't know what else to try. Thanks.
>
Hello,
two observations: Your functions return complex values for k>w/r.
a[k,w]==0 returns True or False.
I suggest you think about your equations.
Alois